1. Field of the Invention
The present invention relates to a shift range switching apparatus for switching the shift range of an automatic transmission, a parking lock apparatus and an engagement switching apparatus for a vehicle.
2. Description of Related Art
In recent years, there are used shift range switching apparatuses constituted including a shift range switching mechanism mounted on an automatic transmission of a vehicle, a drive source (an electric motor, for example) to drive the shift range switching mechanism, and a control device to control the drive source in accordance with a shift lever operation by a vehicle driver to switch the shift range of the automatic transmission as desired.
Some of such shift range switching apparatuses have means to detect abnormality in the drive source by detecting whether or not the shift range has been switched as commanded by the vehicle driver's shift lever operation. For example, refer to Japanese Patent Application Laid-Open No. 2007-32819.
On the other hand, it is known to provide an electric vehicle or a hybrid vehicle not having an automatic transmission with a parking lock apparatus which includes a parking lock mechanism mounted on the drive apparatus of the vehicle to switch between the parking lock state and non-parking lock state. Further, it is known to provide an electric vehicle which includes in-wheel motors serving a drive apparatus of the electric vehicle with a parking lock apparatus to prevent the axle shaft of the vehicle from rotating.
However, the technique as disclosed in the above patent document has a problem in that abnormality in the drive source cannot be detected until the vehicle driver operates the shift lever. On the other hand, the above electric vehicle or hybrid vehicle not having an automatic transmission and provided with the parking lock apparatus has a problem that it is not possible to detect abnormality in the drive source unless the vehicle driver operates the shift lever and performs a parking lock operation.